"is only in the order of a few tenths of a degree C, and definitely less than 0.4°C.

At the current rate of increase of 2ppmv/year it will take 193 years to achieve this doubling. A 0.4°C temperature increase caused by this doubling of CO2 in 193 years is only a year to year temperature increase of just 0.002°C; i.e. 0.18°C by 2100."